Rich, savory, and topped with bubbling melted cheese, homemade French onion soup is classic comfort food built from a handful of simple ingredients. Slowly caramelized onions create a deep sweetness that balances the rich beef broth, while toasted bread and melted Gruyère turn each bowl into a hearty, satisfying meal.
The secret is patience. Giving the onions enough time to caramelize properly creates the deep color and complex flavor that makes French onion soup so distinctive.
Classic French Onion Soup
This recipe slowly caramelizes onions in butter before simmering them with wine, beef broth, and fresh herbs. Each bowl is finished with toasted baguette and plenty of Gruyère cheese before being broiled until golden and bubbling.
Ingredients
For the Soup:
- 4 large yellow onions, thinly sliced
- 3 tbsp unsalted butter
- 1 tbsp olive oil
- 1 tsp salt
- ½ tsp granulated sugar, optional
- 2 cloves garlic, minced
- ½ cup dry white wine
- 6 cups beef broth
- 1 tbsp Worcestershire sauce
- 2 sprigs fresh thyme
- 1 bay leaf
- ½ tsp freshly ground black pepper
- Salt, to taste
For the Topping:
- 1 baguette, sliced into 1-inch pieces
- 1½ cups Gruyère cheese, freshly grated
- ½ cup Parmesan cheese, freshly grated
- Fresh thyme, for garnish
Instructions
1. Slice the Onions
Peel the onions and slice them thinly and evenly.
Consistent slices help the onions cook at approximately the same rate and prevent smaller pieces from burning before the others caramelize.
2. Start Cooking the Onions
Heat the butter and olive oil in a large Dutch oven or heavy-bottomed pot over medium heat.
Add the onions and salt, then stir until everything is evenly coated.
Cook for approximately 10 minutes, stirring occasionally, until the onions begin to soften.
3. Caramelize the Onions
Reduce the heat to medium-low and continue cooking for approximately 35–50 minutes, stirring regularly.
The onions should gradually become soft, deeply golden brown, and significantly reduced in volume.
If desired, add the sugar once the onions have softened to encourage browning.
Avoid rushing this step with excessively high heat. Deep caramelization is what creates the soup's signature flavor.
4. Add the Garlic
Stir in the minced garlic and cook for approximately 30 seconds, until fragrant.
5. Deglaze the Pot
Pour in the white wine and use a wooden spoon to scrape the browned bits from the bottom of the pot.
Simmer for 3–5 minutes, allowing the wine to reduce slightly.
6. Add the Broth
Pour in the beef broth and Worcestershire sauce.
Add the thyme, bay leaf, and black pepper. Bring the soup to a gentle simmer.
7. Simmer the Soup
Reduce the heat and simmer uncovered for approximately 25–30 minutes.
Remove the thyme sprigs and bay leaf, then taste and adjust the salt and pepper as needed.
Prepare the Cheesy Toast
8. Toast the Baguette
Preheat the oven to 400°F (200°C).
Arrange the baguette slices on a baking sheet and toast for approximately 5–8 minutes, flipping halfway through, until lightly crisp on both sides.
9. Assemble the Soup
Preheat your oven's broiler.
Place oven-safe soup crocks or bowls on a baking sheet and ladle the hot French onion soup into each one.
Place a toasted baguette slice on top of each bowl.
Generously cover the bread with shredded Gruyère and a little Parmesan.
10. Broil Until Golden
Carefully place the bowls under the broiler for approximately 2–4 minutes, watching closely.
Remove them once the cheese is completely melted, bubbling, and developing golden-brown spots.
Allow the bowls to cool slightly before serving, as they will be extremely hot.
Why This Recipe Works
Slowly caramelizing the onions develops the soup's characteristic combination of sweetness, savoriness, and deep roasted flavor. Deglazing the pot with wine captures the flavorful browned bits that develop during caramelization and incorporates them back into the broth.
Gruyère is particularly well suited to French onion soup because it melts smoothly while providing a rich, nutty flavor. Toasting the baguette before adding it to the soup also helps it maintain some structure beneath the broth and melted cheese.
Tips for the Best French Onion Soup
- Slice the onions evenly so they caramelize at a similar rate.
- Don't rush the caramelization process by turning the heat too high.
- Use a heavy-bottomed pot to help distribute heat evenly.
- Deglaze the bottom of the pot to incorporate the browned bits into the broth.
- Use freshly grated Gruyère for better melting and flavor.
- Toast the bread first so it doesn't immediately become overly soggy.
- Watch closely while broiling because the cheese can go from golden to burnt very quickly.
- Use oven-safe bowls if finishing individual servings under the broiler.
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